A wide variety of hearing aid instruments are known in the art. Most hearing aids, worn in the ear (ITE) or behind the ear (BTE) occlude to some degree the ear canal, causing an occlusion loss. Occlusion loss is described as a difference between performance of an open ear response (REUR—real ear unaided response) and the performance of an ear with a hearing aid in place but turned off (REAR—real ear aided response with hearing aid turned off). Therefore, placing a hearing aid in the ear eliminates the natural ability of the patient's concha and the ear canal to produce a resonance between, e.g., 2000 and 4000 Hz (hertz), which naturally increases sounds entering the ear. This important feature allows human ear to better understand speech information. The average enhancement is about 16 to 20 dB. It can be clearly seen that a loss of 16 to 20 dB (loss of REUR) in addition to a loss due to a mechanical structure of the hearing aid can create a significant occlusion loss of sometimes up to 40 dB at frequencies between 2000 and 4000 Hz. This presently described hearing aid is configured to eliminate and/or significantly reduce such loss (terms “occlusion loss” and “insertion loss” when a hearing aid is inserted into an ear but turned off are used interchangeably).
Also, most hearing aids—either ITE or BTE—positioned within the ear canal create an occlusion effect. That is, the occlusion effect is associated with the sensation or feeling that the patient's head is “at the bottom of the barrel,” with the patient's own voice becoming intolerably loud. This is often related to a patient's rejection of the amplification due to the patient's discomfort with the patient's own voice.
Placing an earmold or a shell of a custom made hearing aid within the ear canal can produce a low frequency amplification of the patient's voice of between about 10 and 20 decibels. This can relate to a perceived loudness increase in the patient's own voice of about four times the actual loudness of the patient's voice.
Accordingly, there remains a need in the art for a hearing aid that avoids the occlusion loss and occlusion effect problems described above.